Paragraphs should move on using the basis of
furthering the argument. This can be achieved in several ways:

Sequential writing – where one event follows naturally from another
Elaborative writing – where you develop a point made previously
Contrasting/comparing – where an idea contradicts or questions a point in a preceding paragraph
These are just a few ideas. There are many more and your choice may be determined by the type of
essay/argument you are constructing.